Here's the part Microsoft doesn't tell you -- the part the tech press neglects to mention: Bing Smart Search works by snooping on the searches you perform on your Windows 8.1 computer (there's no Smart Search in Windows 8). Windows watches as you run local searches. Unless you specifically, explicitly search for Settings or Files, Smart Search bundles up all of your search terms and sends them to Bing, along with whatever tracking information Windows has at hand. (Perhaps your Windows account?) [emphasis mine -mfn]